<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>盒子模型</title>
    <style>
        div {
            width: 100px;
            height: 100px;
            border-top: 5px solid pink;
            border-bottom: 5px solid black;
            border-left: 5px solid black;
            border-right: 5px solid black;
            /*padding-top: 10px;*/
        }
    </style>
</head>
<body>
<div>
    你好，我是一个一个一个啊
</div>
</body>
</html>